1. Field of the Invention
The present invention relates to an image processing apparatus and system which receive image data (to be referred to as PDL data hereinafter) described in a page description language (PDL) and form an image on the basis of the PDL data.
2. Description of the Related Art
In recent years, a system which receives a print job (including PDL data as data to be printed) from a host computer through a network, converts (to be referred to as image development hereinafter) the PDL data included in the print job into print data in an image processing apparatus, and sends the print data to a printing device such as a high-quality color copying machine, thereby printing the print data on a paper sheet or OHP sheet has already been proposed. Such processing of causing a printing device to print image data through a network is called remote printing.
A system for apparently causing one image processing apparatus to perform control for two color copying machines has also been proposed.
In this conventional system, image development for the two color copying machines is performed by running one PDL developing task in the image processing apparatus. When a print job for one color copying machine is sent while image development for printing in the other color copying machine is being performed, the user who has sent the print job must wait until the first image development processing is ended, and printing is complete. Especially, a heavy print job for a large quantity of image data takes a long time for image development, so the user must wait for a long time.
Assume that an engine error is generated on one color copying machine side. In this case, printing cannot be continued unless some measure is taken, e.g., jammed sheets are removed. Some image processing apparatuses reject subsequent print jobs because, in practice, printing is disabled. Some apparatuses perform only image development for a predetermined number of frame buffer pages because of the limited capacity of the internal image frame memory, and thereafter, perform no image development anymore.
Assume that, in such a system, a user issues a print request to a color copying machine having no error. Since the image processing apparatus has only one PDL developing task, the apparatus does not accept the print request although the color copying machine can print in fact. For this reason, the user must wait until the engine error of the other copying machine is canceled, and the print job which has caused the engine error is completely processed.
As described above, the conventional printing system has a relatively low productivity because the available resources cannot be sufficiently utilized.